University of Michigan - Ann Arbor

A representative sample is a study sample that is similar to the broader population in important respects. It is crucial for researchers to obtain a representative sample so they can appropriately generalize their findings from the small subset of participants to the entire population of interest.

Representative Sample

Why is it important to use a representative sample in research?

Which of the following best describes a representative sample?

What is a key characteristic of a representative sample in research?

Which of the following is a benefit of using a representative sample in research?

The primary purpose of using a representative sample is to enable the generalization of research findings to the broader population. By accurately reflecting the composition of the population, a representative sample helps ensure that the results are not skewed by sample bias.

Generalization and Bias with Representative Samples

An example of a non-representative sample would be measuring the height of women in a single classroom that happens to include the women's basketball team. Because basketball players are typically taller than average, this sample would be biased and would not accurately reflect the height distribution of all American women. To create a more representative sample and a natural bell curve, one would need to measure the heights of a much larger and more diverse group, such as all women at a school.

Example of a Non-Representative Sample

If researchers cannot test all algebra students in a city, they might select a group of about 200 students that accurately reflects the city's overall composition. By using this representative sample, they can confidently generalize their findings to the entire population of algebra students without introducing bias.

Example of a Representative Sample

The standard deviation is the most widely used measure of variability, representing the average distance that individual scores within a distribution deviate from the mean.

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